Recently, the Second Circuit Court of Appeals of the Auxiliary Center of the Fifth Region approved non-bindinglegal opinion number (V Región) 2o. 7 C (10a), titled: "Relative Nullity of the Contract. A seller who learns thatthe purchaser did not have legal capacity to enter into a contract lacks standing to bring a claim if the selleraccepted the execution of such and received a benefit, in accordance with the principle of contractual good faith.”In this legal opinion, the court found that a plaintiff who intends to file a claim alleging that the person withwhom he/she entered into a contract lacked the legal capacity to do so in an attempt to obtain relative nullity ofthe respective contract, when he/she received a benefit from such contract at the respective moment, lacksstanding to bring such a claim. The foregoing is consistent with the principle of contractual good faith recognizedin Mexico’s Federal Civil Code, which provides that once a contract is perfected, the parties are bound not onlyby the obligations expressly undertaken therein, but also by those legal consequences which given their naturearise in accordance with good faith, custom or law, and whose validity and performance cannot be left to thediscretion of one of the contracting parties. Therefore, a person may not demand the relative nullity of a contractthat he/she entered into and accepted at the time of contracting, believing such to be valid, when he/she receiveda benefit for years, also applying the provision of the same Code which provides that the legal incapacity of oneof the parties may not be invoked by the other to his/her own advantage.